Two of the phones will be built around screens using OLED technology, the same type of display in the iPhone X. One will have an LCD screen, the type of display on the iPhone 8 and all previous iPhones.

The biggest question for investors is what the mix will be between the three devices. The iPhone X, which is the only phone with an OLED screen, starts at $999, making it one of the most expensive smartphones in the world.

That price tag is largely due to its screen technology. The OLED part costs $100, whereas LCD iPhone screens cost about $40, according to analysts cited by The Journal. If Apple sells more OLED iPhones, the iPhone will have a higher average price.

That’s part of the reason Apple may be shifting its production plans to make more LCD iPhones than OLED iPhones, The Journal reported, citing executives at parts makers with direct knowledge of the matter. They say Apple anticipates that the less expensive models will be more popular.

OLED screens can have better image quality than LCD displays, as well as darker blacks and lower power consumption.